Prior methods of assembling an innerspring mattress typically involve the following operations:
The materials used in the construction are fed to (or otherwise gathered by) a person called an "assembler". A work table is typically needed. If the table is stationary, the assembler walks around the table as necessary to perform the mattress-assembly operations. If the table is a swivel-type table, the assembler stands at one area and swivels the table around. (As can be appreciated from the following description, prior methods of assembling innerspring mattresses required the assembler to work all around the perimeter of the mattress.)
Next, an innerspring is placed on the table. If the spring calls for edge supports, the supports must typically be attached first. This is typically done by the use of an air-tool. The air tool is called a Hog-Ring Gun or a clipping gun. The gun is controlled by a trigger and is powered by air. The gun is heavy and dangerous and is frequently the cause of injuries. The gun releases a U-shaped clip which engages a coil spring or a border rod of the innerspring; and then, with the force of air, the jaws of the gun crimp the clip into a closed O-shaped loop.
The assembler must first apply and clip an "insulator" to the innerspring to keep it from shifting. Then, the assembler lays out a "filling material". The filling material could be either a single layer or multiple layers of combined cushioning such as cotton, foam, poly-foam, wool, polyester, or garment fibers. Then all these filling components are laid out evenly over the sub-assembly, (which is already covered with the insulator). The filling material must cover the edges of the innerspring sub-assembly.
The assembler then begins installation of a "top panel". The top panel would typically already have had a strip of cloth material sewn onto it with approximately four inches hanging all around the edge of the panel. This strip of material that hangs over the top panel is called the "flange cloth". The assembler must place this panel over all the filling material and square all four corners of the panel. The assembler then clips each corner of the flange cloth to the corner coils in order to hold the panel in place as he flips the entire half-assembled innerspring sub-assembly over so that he can attach (clip) the flange cloth to every coil of the innerspring perimeter. However, before he starts the clipping operation, he must constantly pull and tuck the material and the top panel so it sits evenly and square, and so that the corners are square to the ends and sides of the assembly. All the filling material must be under the four inch flange cloth. Once that side is completed, the same process must be duplicated for the second side of the sub-assembly. Then the four corner coils must be filled up--in order to produce full and rounded corners. Then the mattress border must be placed around the perimeter. Then the completed mattress must be physically picked up and placed onto a skid, table or conveyor.
Typically, all of the above-described operations are manually performed by the assembler. The above-described operation is physically demanding, difficult and dangerous. It takes months to train an assembler. And even after properly trained, production is slow and laborious, which results high costs.
Prior methods of innerspring mattress cover assembly and tape edging typically involve an "operator", a large table, and a sewing head attached to a carriage. The carriage portion typically comprises a motor and drive belts. The table typically has a toothed rail which engages with a drive gear. The carriage portion also contains a brake which the operator regulates by pushing in with his knee. With the switch turned on, the machine automatically moves around the table.
The operator typically first picks up the mattress off of a skid, table or conveyor and places it on the table and positions it so that he can start joining the border to one of the above-described panels. Typically, the operator only has 3/4" or less of the panel edge to hold onto. He pulls the panel edge by hand into a "binder" which contains the binding (i.e. tape). At the same time, he must pull upward on the border and feed it into the binder with his other hand.
After the first side is sewn, the operator must flip the entire mattress sub-assembly over and then repeat the sequence. Assembly of the second side of the mattress cover is even more difficult than the first, because the border has already been sewn to one side. Thus, the edge of the mattress must be pushed down with one of the operator's elbow and arm, while the he pulls up on the border and struggles to get it into the binder with his other hand.
After the mattress is bound (i.e. taped) on both sides, it then must be picked up again and placed into position for inspection and packing. It is noted that the typical prior method of mattress cover assembly requires that the entire mattress assembly to be picked up to be placed on the table for taping, then flipped over so that the second side may be taped, then picked up again and placed for final inspection and packing. The prior laborious mattress cover assembly procedure is the most difficult procedure involved in the assembly of a mattress. It typically takes years to train a good operator to assemble mattress covers using prior assembly methods.
Additionally, because of the difficulty involved in the labor-intensive prior methods of mattress cover assembly, operators have frequently suffered from distorted fingers and diseases of the hands, and from injured backs.
Furthermore, the equipment used in the prior methods of mattress cover assembling is expensive and typically requires constant care and maintenance.